Specifications
LCD Directory Structure
Disks on a Small Computer System Interface (SCSI) bus are one example of equivalent resources.
With the SCSI locking (or reserve) mechanism, only one server can own the lock for a disk device at
any point in time. This lock ownership feature guarantees that two or more servers cannot access the
same disk resource at the same time.
Furthermore, the dependency relationships within a hierarchy guarantee that all resources that
depend upon the disk, such as a file system, are in service on only one server at a time.
LCD Directory Structure
Major subdirectories under /opt/LifeKeeper:
l config. LifeKeeper configuration files, including shared equivalencies.
l bin. LifeKeeper executable programs, such as is_recoverable. See Fault Detection and
Recovery Scenariosfor descriptions.
l subsys. Resources and types. LifeKeeper provides resource and type definitions for the
shared SCSI disk subsystem in scsi and for the generic application menu functions in gen.
When you define an application interface, you create directories under subsys.
l events. Alarming events. See LifeKeeper Alarming and Recovery for further information.
The structure of the LCD directory in /opt/LifeKeeper is shown in the topicStructure of LCD Directory
in /opt/LifeKeeper.
LCD Resource Types
The LCD is maintained in both shared memory and in the /opt/LifeKeeper directory. As highlighted on
the directory structure diagram, subsys contains two application resource sets you can use to define
your application interface:
l gen - generic application and file system information
l scsi - recovery information specific to the SCSI
These subdirectories are discussed in Resources Subdirectories.
LifeKeeper Flags
Near the end of the detailed status display, LifeKeeper provides a list of the flags set for the system.
A common type is a Lock LCD flag used to ensure that other processes wait until the process lock
completes its action. The following is the standard LCD lock format:
!action!processID!time!machine:id.
These are examples of general LCD lock flags:
l !action!02833!701236710!<servername>:filesys. The creation of a filesystem
hierarchy produces a flag in this format in the status display. The filesys designation can be a
196User Guide